Balloon Occlusion Test

What is a Balloon Occlusion Test?

There are four main arteries supplying blood to your brain. In most people, there are links between these four arteries that allow for one of the arteries to be blocked without significantly affecting the amount of blood reaching the brain. The balloon occlusion test is usually done if there is an abnormality (for example, aneurysm or tumor) in one of the four main arteries. It is a way to see whether one artery can be temporarily or permanently blocked without significantly affecting the level of blood in your brain. The procedure utilizes an X-ray and a special dye to create detailed images of your arteries and a small balloon, which when inflated will temporarily block your artery.

Franklin Moser, MD, Director of Interventional Neuroradiology heads our team of imaging physicians, nurses and technologists who specialize in these procedures.

What Does the Procedure Involve?

The Balloon Occlusion Test first involves an angiogram, which is an examination of the blood vessels using x-rays, that determines how well blood moves through the vessels of the brain, lung, abdomen, arms or legs. After the pictures are taken of the blood vessels, a catheter with a small non-detachable silicone balloon on the end is threaded up from the femoral artery at the groin into the blood vessel of interest. This tube is placed through the same hole as the other catheter making it unnecessary to stick the artery again. After the balloon is placed in the artery to be tested it is gently inflated to block flow through the artery. A dose of blood thinning medicine is given through a vein just before this so that the blood does not clot when the flow stops.

While the balloon is inflated, clinical testing is conducted. Every few minutes, testing is performed to check your hand grip, foot flexion and extension, language, memory, orientation, and facial expression. If you have good connections or collaterals, the other arteries send enough blood to the brain so there is no change in the brain function. In this case the balloon is usually left in place for thirty minutes, then deflated and removed. If your brain lacks these connections and not enough blood gets to the brain, you may develop weakness in an arm, or difficulty speaking. In this event the balloon is immediately deflated and removed. Once removed, the blood flow is restored and the weakness goes away, usually within seconds.